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INTRODUCTION to Indoor Air Quality


(IAQ) History of Indoor Air Quality Greek philosophers, 500 BC, concerned with air quality in mines Roman, Pliny the Elder, advised masks for stonecutters and ... – PowerPoint PPT presentation

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Title: INTRODUCTION to Indoor Air Quality

INTRODUCTIONto Indoor Air Quality
History of Indoor Air Quality
  • Greek philosophers, 500 BC, concerned with air
    quality in mines
  • Roman, Pliny the Elder, advised masks for
    stonecutters and asbestos miners
  • Early 1800s, first recommendations for
    ventilation standards to control odor
  • Florence Nightangle(1858) recommended air
    exchange rate of 25 cfm/person to avoid
    re-infection in hospitals

Questions Regarding Indoor Air Quality
  • What is Indoor Air Quality?
  • What is the relationship between indoor and
    outdoor air quality?
  • Why should you be concerned about the quality of
    air that you breath?
  • What causes indoor air problems?
  • What are the factors affecting indoor air
  • How does outdoor air enter a house?
  • What are the health effects from indoor air
  • Can you give examples of indoor air contaminants?
  • Do you know the origin of air quality problems?
  • What are the guidelines for IAQ?
  • What is an IAQ prediction model?
  • What are the strategies to improve indoor air

What is Indoor Air Quality ?
  • Refers to good and bad effects of the contents of
    air inside a structure on its occupants
  • Good indoor air quality(IAQ) has no unwanted
    gases or particles in it at concentrations which
    will adversely affect someone
  • Poor indoor air quality has gases or particles
    in excessive concentration so as to affect the
    satisfaction or health of occupants

Relationship between Indoor and Outdoor Air
  • Indoor pollutant concentrations may be higher or
    lower than outdoor air concentrations
  • Outdoor contaminants may be present indoors at a
    sufficient concentration to affect the occupants
  • Example Pollen and mold spores from
    outdoors causes
  • hay fever and allergies indoors

Why should you be concerned about the quality of
air that you breath?
  • The contaminant indoor air could damage peoples
  • Indoor air pollutants are among the top five
    environmental risk
  • People spend about 90 of their time indoors and
    so the health problems that result from exposure
    to indoor pollution increases
  • According to World Health Organization (WHO)
    approximately 30 of all commercial buildings
    have significant IAQ problems

Statistics on Indoor Air Pollution
  • Indoor radon exposure is estimated to be the
    second leading cause of lung cancer (American
    Lung Association )
  • Environmental tobacco smoke (ETS) causes an
    estimated 3,000 lung cancer deaths and 35,000 to
    50,000 heart disease deaths in non-smokers, as
    well as 150,000 to 300,000 cases of lower
    respiratory tract infections in children under 18
    months of age each year (ALA)
  • 1.4 million buildings in the United States have
    indoor problems (OSHA)
  • Legionnaires Disease strikes 25,000 people and
    kills over 4000 people every year (Center for
    Disease Control)

Sources of Pollutants
  • Normal Biological Processes - people and pets
    generate carbon dioxide, moisture, odors and
  • Combustion appliances such as wood stoves, gas
    stoves, furnaces, fireplaces and gas heaters
  • Use of consumer products such as spray cans, air
    fresheners, spray cleaners and construction
  • Cigarette smoking
  • Soil under and around buildings
  • Appliances such as humidifiers, air conditioners
    and nebulizers

Sources involved in IAQ problems
  • Evaluations by National Institute for
    Occupational Safety and Health (NIOSH) for
    studies on more than 500 Indoor Air quality
    health hazard cases

Reasons of IAQ Problems based on NIOSH study
Factors affecting IAQ
  • Meteorological conditions
  • Ventilation condition
  • Pollutant decay
  • Pollutant removal
  • Pollutant release
  • Permeability of structures
  • Outdoor air quality

How does Outdoor Air enter Indoors
  • Infiltration - outdoor air flows into the house
    through openings, joints, and cracks in walls,
    floors, and ceilings, and around windows and
  • Natural Ventilation - air moves through opened
    windows and doors
  • Mechanical Ventilation - from outdoor-vented fans
    that intermittently remove air from a single
    room, such as bathrooms and kitchen, to air
    handling systems that use fans and duct work to
    continuously remove indoor air and distribute
    filtered and conditioned outdoor air to strategic
    points throughout the house

Health effects due to Indoor Air Pollutants
  • Headaches
  • Nausea
  • Respiratory infections
  • Asthma
  • Hypersensitivity pneumonitis
  • Humidifier fever
  • Legionnaires disease
  • Lung cancer

What is Sick Building Syndrome (SBS)?
  • Condition of a building in which more than 20 of
    the occupants are suffering from adverse health
    effects but with no clinically diagnosable
    disease present
  • It is a condition of a building not of the
  • It takes place due to long term exposure to low
    levels of contaminants

Health Symptoms and Possible Contaminants
Health Symptoms and Possible Contaminants
List of Pollutants affecting IAQ
  • Volatile organic compounds (VOCs)
  • Dust and dirt
  • Radon
  • Bio-aerosols
  • Environmental tobacco smoke (ETS)
  • Respirable Particulate Matter (RPM)
  • Carbon and Nitrous Oxides

Origin of Indoor Air Quality Problems
  • Inadequate ventilation
  • Pollutants from material processed inside the
  • Pollutants drawn in from outside air
  • Biological contamination
  • Pollutants from building materials and
  • Saving energy

Guidelines for IAQ pollutants
Guidelines (contd.)
Guidelines (contd.)
What is an IAQ Prediction Model?
  • It is basically a Mass Balance Equation
  • The equation is
  • (Pollutant flowing) (Pollutant flow out)
  • (Source emissions) (Sink removal)
  • Indoor air pollution accumulation
  • Units are mass/time

Strategies to improve Indoor Air Quality
  • Pollutant Source Control
  • Increased Ventilation
  • Dehumidification
  • Use of Air Cleaners
  • Dust collectors
  • Filters